Elevating dolly



A. J. TAYLOR ELEVATING DOLLY July 28, 1959 5 Sheets-Sheet 1 Filed Nov. 4, 1955 July 28,1959 A, TAYLOR- 2,896,909

' ELEVATING DOLLY Filed. Nov. 4, 1955 '5 h ets-Sheet 2 July 28, 1959 Filed Nov. 4, 1955 A. J. TAYLOR ELEVATING DOLLY 5 Sheets-Sheet 3 July 28, 1959 A. J. TAYLOR 2,896,909

ELEVATING DOLLY Filed Nov. 4, 1955 I 5 heets-sheet 4 July 28, 1959 A. J. TAYLOR ELEVATING DOLLY Filed Nov. 4, 1955 5 Sheets-Sheet 5 aweW'gom:

United Sta Patmt Northrop Aircraft, Inc., Hawthorne, Calif., 11 corporation of California Application November 4,1955, Serial No. 544,850 Claims; (21. 254-9 This invention relates to material handling equipment and more particularly to elevating type dollies especially useful in the handling and positioning of heavy equipment.

Elevating type dollies quite frequently are limited in their use and application. In the handling of heavy equipment the complete dolly structure is normally placed beneath the equipment to be moved or repositioned prior to the release thereof from supporting structure. For this reason the design and construction of such dollies are materially limited especially in respect to size and clearance limitations. For example, if a dolly is designed for handling and positioning equipment located at extensive distances above a given surface it is difiicult to incorporate in the design of the dolly structure permitting it to be placed beneath equipment located at relatively small distances above the aforementioned surface. It is obvious that the above objectional feature must be overcome if the same piece of equipment or apparatus is to be utilized for both high and low lifts.

Accordingly it is an object of'the present invention to provide an elevating type dolly which may be used for both relatively high and relatively low lifts.

Another object is to provide an elevating type dolly incorporating structure functioning to insure movements of the elevating portion thereof through an extensive vertical range.

Another object is to provide an elevating type dolly the base portion of which may be lowered to contact a supporting surface and thereby provide a firm, stable foundation for the dolly.

Another object is to provide an elevating type dolly incorporating means whereby the dolly may be steadied to provide a firm, stable foundation therefor other than the stability provided by the base portion.

Another object is to provide an elevating type dolly which is simple in design yet rugged in construction, economical to manufacture, and which may be easily adapted to any purpose for which it is intended.

Although the characteristic features of the present invention are particularly pointed out in the appended claims, the invention itself, also the manner in which it may be carried out, will be better understood by re- 2,896,909 Patented July 28, 1959 Figure 6, is a partial sectional view taken along the line 6-6 of Figure 3.

Figure 7 is a partial sectional view taken along the line 7-7 of Figure 2.

Figure 8 is a detail view of a typical radius rod utilized with the dolly of Figure 1. I

. Figure 9 is a detail view of a front wheel suspension of the dolly of Figure 1.

Referring to the drawings and particularly Figure 1 an elevating dolly 11 of the type disclosed herein is shown. The dolly 11 includes a base assembly 12, an elevating assembly 14, a cradle assembly 16, fore and aft scissor type linkage assemblies 17 and 18, respectively, hydraulic equipment19 (not identified in Figure 1), and wheel and linkage assemblies 21 and 22.

l The assembly 12 consists of a plurality of elongated channel members 24-28, inclusive, joined together by corner castings 29-32, inclusive, to provide a substantially co-planar lo'wer frame member 23 of substantially rectangular configuration as viewed in Figure 2. The channel member 28 extends between the side members 24 and 25 intermediate their end portions to provide rigidity to the frame member 23. Spaced upstanding lug portions 33 and 34 extend from each of the castferring to the following description taken in connection thereof broken away in each instance.

Figure 5 is a diagrammatic showing of the hydraulic system employed in the dolly of Figure 1.

ings 29-.32, inclusive, to provide pivotal supports for the inner ends of upper and lower supporting links 36 and 37, respectively, of the wheel linkage assemblies 21 and 22. Additional spaced upstanding portions 38 and 39 extend from each of the corner castings to provide pivotal supports for the lower links 41 of the assemblies 17 and 18 as best seen in Figure 6.

The assembly 14 includes a pair of channel members '42 and 43 maintained in spaced parallel relationship, with their respective open sides facing downwardly, by elongated members 44 and 46 located at the ends of the channel members. The members 44 and 46 are of U- shaped configuration both in lateral and longitudinal cross-section to provide a box-like structure. The members 44 and 46 are attached to the members 42 and 43 and are positioned in the assembly 14 so that the leg portions thereof are upstanding to receive movable members 47 in the respective cavities provided therein as best seen in Figures 6 and 7. The members 47 are mounted for longitudinal movement, with respect to the members 44 and 46, on rollers 48 pivotally mounted in the upstanding side leg portions of the members 44 and 46. Roller assemblies 49 are pivotally mounted adjacent each end of the members 47 and include a pair of pivotally mounted rollers 51 each having a concave outer surface portion adapted to receive an arcuate tubular member 52 of the assembly 16.

Longitudinal movement is imparted to the members 47, with respect to the members 44 and 46, by a screw jack 53 (Figure 6) threadably engaging respective mating nut members 54 fixedly secured to the members 44 and 46. The inner ends of the screw jacks 53 are rotatably secured to the members 47 and rotational movement is imparted thereto by ratchet handles 56. From the above description, and by referring to Figure 6, it will be apparent the members 47 may be moved laterally, with respect to the dolly 11, in accordance with rotary movement of the jacks 53. The members 47 are provided with plane surfaces 57 which provide bearing surfaces for the rollers 48 and between which movement occurs during the aforementioned lateral movement of the members 47. I

The cradle assembly 16 includes the aforementioned arcuate tubular members 52 the end portions of which are attached to I-beam members 58, extending longitudinally with respect to the assembly 14, by means of fittings 59. In the embodiment shown the curvature of the tubular members 52 is constant throughout their length. Thus it is seen thatthe members 52 may be rocked, in a'la'teral direction about an .axis extending longitudinally with respect to the assembly 16, in the rollers '49. The members 52 are retained in the concave portions of the rollers 49 by means of U-shaped straps 61.

Rocking movement is imparted to the assembly 16 by a screw jack 60. One end portion of the screw jack 60 is suitably attached to one of the tubular members 52'while its other end is suitably attached to the member 44.

Supporting pad assemblies 62 are mounted on the upper flanges of the members 58 and are adapted to receive and support equipment to be handled by the dolly 11, for example, a jet engine 65 as best seen in Figure 4. The assemblies 62 may be moved longitudinally along the members 53 and may be releasably secured at any desired position thereon. Small longitudinal movements may be imparted to one of the assemblies 62, and consequently to the jet engine 65, by means of a screw jack 70 which may also be moved to a plurality of positions located longitudinally along the beam 58.

The base assembly 12 and elevating assembly 14 are joined together for relative vertical movement by the aforementioned fore and aft linkage assemblies 17 and 18, respectively. Each of these linkage assemblies consists of the previously referred to lower links 41 and upper links 63, respectively. In addition the upper links of the assemblies 17 each have an extension 73 fixedly secured thereto, as by welding or the like, and having a slight angular relationship with respect to the link 63 substantially as shown in Figure 1. Also the assemblies 17 include an auxiliary link 64. The assemblies 17 and 18 will hereinafter be referred to as the main and auxiliary linkage assembliw, respectively.

Except for the extensions 73 and auxiliary links 64 the construction of the assemblies 17 and 18, and the method of attaching these assemblies to the assemblies 14 and 23, are the same, therefore, a description of the assemblies 17 will be applicable to the assemblies 18 except as noted above.

Referring then to the main linkage assemblies, one end of each of the links 41 is attached to the spaced portions 38 and 39, extending from the respective corner castings 29 and 31, for pivotal movement about an axis D (Figure 6). Depending from the other end of each of the links 41 is a plate-like element 68 between which a cross-member 66 extends in fixed relationship. One end of each of the links 63 is secured to the member 44, at the outboard ends thereof as best seen in Figures 4 and 6, for pivoted movement about an axis E. The other ends of the links 63 are mounted for pivoted movement about an axis F located in upstanding portions 72 formed at the ends of the links 41 which are spaced from the castings 29 and 31. A tubular crossmember 67 also extends between and is fixedly secured to plate-like elements 76 which depend from the ends of the links 63 which are adjacent the members 41.

Pivotally attached to and extending between the crossmembers 66 and 67 at the midportions thereof is a hydraulic actuator 75. The actuator 75 is a cylinder and piston type and is equipped with a conventional safety device 79 functioning to prevent actuator collapse in the event of fluid failure.

v Disregarding for the moment the extensions 73, axuxiliary links 64, and their accompanying functions, it will be apparent that similar portions of the assemblies 14 and 16 will remain in horizontal planes as equal quantities of fluid are caused to enter or exit from the actuators 75. Under the above conditions movements of the assemblies 14 and 16 will be in a true vertical direction, that is the assemblies 14 and 16 will not be displaced longitudinally, with respect to the base assembly 12, as they are moved through their operating ranges. The above described movement of the assemblies 14 and 16 is similar to the movement imparted to the supporting pad of a scissor type jack at such times as the screw of the jack is actuated. The above assumes that the assemblies 14 and 16 remain in a complete balanced relationship with respect to the base assembly 12. In practice, however, the above balanced relationship is impossible to maintain due to the fact that the main'and auxiliary linkage assemblies 17 and 18 are pivotally attached to both the assemblies 12 and 14. If it was not for the extensions 73 and auxiliary rods' 64, cooperating with the main linkage assemblies 17,'the assembly 14 would collapse on the base assembly 12 in an undesirable manner.

The extension 73 and link 64 constitutes a follower or stabilizing linkage. An axis G,'located at the outer temperminal end of the extension 73, extendsparallel to the axis F and prescribes an arcuate path of substantially constant radius, hereinafter referred to as the original arcuate path of the common axis G, at such times as the assembly 14 is moved vertically through its operating range. One end of the auxiliary link 64 is attached to the terminal end of the extension 73 in a manner to pivot about the axis G. The link 64 is of such a length and its other end is pivotally attached to a respective side member of the assembly 23 at a location causing its common pivotal axis G to follow the arc of a circle substantially coinciding with the original arcuate path prescribed by the axis G.

The operating ranges of the assemblies 14 and 16, as

referred to above, are defined as the respective verticaldistan'ces through which the assemblies 14 and 16 travel in moving between their completely raised and completely lowered positions.

With the auxiliary link 64 attached to the extension 73, in the manner as described above, any tendency for the linkage assemblies 17 to pivot in an undesirable manner about their respective pivotal axes D and E is effectively resisted. Inasmuch as the auxiliary rod 64 diverts the common pivotal axis G only slight amounts from its original arcuate path the movements of the assemblies 14' and 16 will be diverted only slight amounts from true vertical movements as the latter assemblies are moved through their respective operational ranges. Also any load tending to rotate the linkages 18 about their respective pivotal axes will also be resisted by the auxiliary links 64 acting through the assembly 14. i

In the lowered position of the assembly 14 the latter rests on upstanding portions of the castings 29-31, inclusive, and the links 63 are partially recessed in the men1- bers 42 and 43. Also the axes of the actuators 75 are located in the central horizontal plane of the frame member 23. All of these constructional features insures a minimum overall height of the dolly 11 at such times as the assembly 14 is in its lowered position and, therefore, permits the dolly to be placed beneath apparatus stationed at relatively low elevations.

Referring to Figure 3 the operation of the linkage assemblies 17 and 18 will be further explained. In this figure the assembly 14 is shown in its lowered and partially elevated positions by solid and phantom construction, respectively. Assuming the assembly is in its lowered position and fluid is admitted to the actuators 75 causing the latter to exert equal horizontal forces on the members 66 and 67 located at each end of the dolly 11. The force acting on the members 67 is transmitted to the axes E where it is resolved intovertical and: horizontal components. The vertical component acting at E causes the links 63 to pivot about the axes F on the links 41. Inward movements of the outer ends of the links 63 are precluded due to the fact that they are pivotally attached to the rigid assembly 14. They can, therefore, only move in an upwardly direction accompanied by pivotal movement of the links 41 about their axes D. Thus a compound movement is imparted to the links 63 due to their own pivotal movement about the axes F and also due to pivotal action of the links 41 about their axes D.

The above type of construction insures large vertical movement of the assembly 14 for small movements of the actuators 75. Actual tests show that for each linear unit of expansion or retraction of the actuators 75 the assembly 14 is moved through a vertical distance of approximately five linear units of the same magnitude through which the actuators are moved. This multiplication of vertical distance for small movements of the actuators is extremely important in elevating dolly construction as it permits the use of actuators having relatively short strokes and still insures extensive vertical movements of the dollys cradle.

As the main and auxiliary linkage assemblies 17 and 18 are opened and closed the axes E, located respectively at the fore and aft ends of the dolly, normally move substantially in vertical planes directly above the respective pivotal axes D as directed by extensions 73 and auxiliary rods 64. Either end of the assembly 14, however, may be raised or lowered with respect to the other end thereof.

The wheel and linkage assemblies 21 are located at diagonally opposite corners of the frame 23 and the assemblies 22 are located at the other diagonally opposite corners. The upper links 36 of the assemblies 21 are pivotally attached to the spaced portions 33 and 34 by means of continuous pins 81 extending therethrough. The upper links 36 of the assemblies 22 are likewise pivotally attached to the portions 33 and 34 by noncontinuous pins 82 the inner ends of which are secured to the cylinders of hydraulic actuators 84 as by welding or the like. The lower links 37 of the assemblies 21 and 22 arefixedly secured to torque tubes 83 (Figure 9) which are also pivotally mounted in the spaced portions 33 and 34 of the corner castings. The tubes 83 transmit angular movement between the two links 37 located respectively at the fore and aft ends of the frame 23. The outer ends of the links 36 and 37 are provided with ball type sockets 87 by means of which axles 85 of the wheels 86 are mounted for pivotal movement about vertical axes. The piston rods 88 of the actuators 84 are pivotally attached to the lower links 37. Angular movement is imparted to the links 36 and 37 by means of the actuators 84 as presently explained.

The dolly 11 is steered by means of a tow bar 89. The tow bar is attached to a clevis 91 for pivotal movement about a horizontal axis while the clevis is attached to the member 26 for pivotal movement about a vertical axis. Extending between the leg portions of the clevis 91 and pivotally attached thereto is a tie rod 92. The end portions of the rod 92 are pivotally attached to respective arms of U-shaped members 93 which are mounted on the castings 29 and 31, respectively, for pivotal movement about a vertical axis. A radius rod 94 extends between an arm projecting from each of the members 93 and an arm projecting from the axle of each of the front wheels 86. Each of the radius rods 94 are attached to members 93 and the axles 85 of the front wheels by means of ball joints 96 and 97, respectively. The aft assemblies 21 and 22 are also provided with positioning rods 98 similar to the radius rods 94. The rods 98, however, are not used during normal steering operations and are normally attached to the member 27 by ini tial pivotal. means constituting ball and socket type joints 99. p

Each of the rods 94 and 98 are provided with quick disconnect means at a location intermediate their ends. A typical quick disconnect means is shown in Figure 8 in which one of the rods 94 is used for illustrative purposes.- Th'e disconnect means consists of a sleeve 102 normally urged to the position shown by solid construe tion by a spring 103. The rod 94 consists of two pertions 104 and 106. joined by'ma'ting saw-tooth structure formed therein as indicated at 107. With the sleeve 102 moved to the position indicated by phantom con.- struction it will beapparent that the rods 104,a'nd 106 may be readily separated. Stub rods 108 having sawtooth means formed at their free ends are pivotally attached at their opposite ends to the casting 29-32 by alternate pivotal means 109.

Upon separation of the rods 94 and 98 it will be apparent that the wheels 86 may be pivoted through an angle of ninety degrees to a position in which the central vertical planes of the wheels are normal to the longitudinal axis of the dolly 11, substantially as shown by phantom construction in Figure 2. The rod portions, attached to the wheels 86, may then be secured to the stub rods 108 to maintain the wheels in the last mentioned positions. It will be apparent that this construction permits the dolly 11 to be moved in a direction normal to the longitudinal axis thereof and that such a maneuver will be extremely useful in instances where it is not possible to move the dolly in a longitudinal direction into a desired position.

The aforementioned hydraulic system 19 includes a fluid reservoir 111, pumps 112, selector valves 114, and the actuators 75 and 84 as schematically shown in Figure 5. The reservoir, pumps, and selector valves 111, 112, and 114, respectively, are mounted within the member 24. Handles 116, for actuating the pumps 112, and control levers 117, for regulating the flow of fluid through the valves 114, are located in a readily accessible position adjacent the upper surface of the member 24; Flexible tubing 118-121, inclusive, provide fluid communication between the valves 114 and actuators 75 and 84. 'Lines 122 and bypass valves 123, the latter being positioned in the lines extending between the pump 112 and valves 114, allow fluid to bypass the actuators 75 and 84 in the event excessive fluid pressure develops within the hydraulic system.

By utilizing portions of the hydraulic system 19 the assembly 12 may be moved between an elevated position and a lowered or bottomed position. In the elevated position the frame 23 is located a predetermined distance above the surface on which the wheels 86 are resting. In the lowered or bottomed position the frame 23 rests on the aforementioned surface. Thus in the low ered position the frame 23 provides a firm, stable foundation for the dolly 11. Resilient movements due to pneumatic tires which may be mounted on the wheels 86 are effectively eliminated. Also relative swaying movements, occurring at such times as the dolly 11 may be utilized on board ship to position armaments or the like, is also effectively eliminated.

Assuming the assembly 12 is in its raised position and it is desired to move it to its lowered position. Levers 117 are positioned so that a restricted amount of fluid flows from the actuators 84 to the reservoir 111. The force of gravity acts to lower the dolly until the frame 23 is in contact with the surface on which the wheels 86 are resting. The assembly 12 may subsequently be returned to its raised position upon adjustment of the valves 114 and actuation of the pumps 112. In this connection it should be understood that angular movements impartedby the actuators 84 to the links 37, associated with the assemblies 22, are transmitted to the links 37,

bility of binding of the members 36,37 and 94 is pre cluded as the base member 23 israisedand lowered.

" The relationship of the members. 36,37, and 94, as referred to above, will be apparent by referring to Figure 9. In this figure the members 36, 37, 94, and asso, ciated members are shown in a projected relationship on a vertical plane containing the longitudinal axis of the framemember 23. The lines A, B, and C, represent center lines extending between the respective pivotal points of the links 36, 37, and the rod 94. It will be noted that the projected lengths of the lines A, B, and C are equal and bear a parallel relationship with respect to each other. Further this relationship remains as shown during relative movement of the member 23 with respect to the Wheels 86 as the member 23 is raised or lowered. For any position of the frame member 23 the horizontal distances between the respectice pivotal points of the rod 94 and links 36 and 37 on the member 23 and the respective pivotal points of the rod 94 and links 36 and 37 on the axle 85 are equal. Accordingly the lines A, B, and C, considered with vertical lines extending through respective pivotal points, constitute a parallelogram type movement which does not impart undesirable movements to the wheels 86 and precludes the possibility of binding between the wheel linkages and the rods 94 and 98.

In addition to the steadying means described above, i.e., lowering the frame 23 into contacting relationship with a supporting surface, a steady rest unit 124 is mounted in a vertical attitude in each of the corner castings 29-32, inclusive. Each of the units 124 consists of a cylindrical stem 126 and foot or pad portion 127 as best seen in Figure 7. The stem 126 passes through an aperture formed in the corner castings and extends through an upstanding collar 128 formed on the corner castings. Mating apertures are provided in the stems 126 and collars 128 to receive a pin 129 whereby the unit 124 may be secured in a plurality of vertical positions. In the uppermost position of the unit 124 the pads 127 are recessed in the lower portion of the corner castings. It will be apparent that the units 124 may be lowered a predetermined distance below the assembly 12 and secured in this position by the pins 129. Accordingly upon lowering the assembly 12 the dolly 11 will come to rest on the units 124 rather than the base members 23. The steady rest units 124 will be especially useful at such times as the dolly 11 is used on movable surfaces, e.g. the deck of ships and the like.

. While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprises a preferred form of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

What is claimed is:

1. An elevating dolly comprising: a rectangular base structure having fore and aft ends; wheel assemblies mounted at each corner of said base structure normally supporting said base structure in a horizontal attitude; an elevating structure; a plurality of elongated lower links each having a plain and an enlarged end; a plurality of elongated upper links corresponding ends of which are respectively pivotally attached to the enlarged ends of said lower links to provide a plurality of individual link assemblies one of which is mounted at each corner of said base structure; said individual link assemblies providing means mounting said elevating structure on said base structure and allowing said elevating structure to be moved through an operating range between raised and lowered positions when predetermined relative angular movement is imparted to said upper and lower links; a depending plate member mounted at the other end of each of said upper links;first cross-members attached to and extending between the depending plate members located respectively at the fore andaft ends of said base structure; second cross-members attached to and extend ing between the said enlarged ends located respectively at the fore and aft end of said base structure; and'a pair of elongated bidirectional power means the ends of which are respectively pivotally attached to the said first and second cross-members located at the fore and aft end of said'base structure and function to impart said rela tive angular movement to said upper and lower links.

2. In an elevating dolly the combination comprising: a rectangular base structure having fore and aft ends; an elevating structure; a plurality of elongated lower links each having a plain and an enlarged end; a plurality of elongated upper links corresponding ends of which are respectively pivotally attached to the enlarged ends of said lower links to provide a plurality of individual link assemblies one of which is mounted at each corner of said base structure; said individual link assemblies providing means mounting said elevating struc ture on said base structure and allowing said elevating structure to be moved through an' operating range between raised and lowered positions when predetermined relative angular movement is imparted to said upper and lower links; a depending plate member mounted at the other end of each of said upper links; first cross-members attached to and extending between the depending plate members located respectively at the fore and aft ends of said base structure; second cross-members attached to and extending between the said enlarged ends located respectively at the fore and aft end of said base structure; and a pair of elongated bidirectional power means the ends of which are respectively pivotally attached to the said first and second cross-members located at the fore and aft end of said base structure and function to impart said relative angular movement to said upper and lower links.

3. Apparatus as set forth in claim 2: further characterized in that at such time as said elevating structure is in said lowered position the upper and lower links, comprising each of said individual linkage assemblies, have a juxtaposed relation and said first and second cross-members and power means are located below said lower links.

4. Apparatus as set forth in claim 2: further characterized by including a plurality of auxiliary links corresponding ends of which are pivotally attached to extending ends of each of said upper links and the other ends of said auxiliary links are pivotally attached to said base structure and cooperate with said individual linkage assemblies to restrict movement of said elevating structure to substantially a truevertical movement as the elevating structure is moved through said operating range.

5. In an elevating dolly the combination comprising: a wheeled base structure normally having a horizontal attitude; at least one upper elongated link and at least one lower elongated link each having a longitudinal axis; said lower link having a plain end and an enlarged end; one end of said upper link being pivotally secured to the enlarged end of said lower link; the plain end of said lower link being pivotally attached to said base structure and said links having an initial position in which said links are juxtaposed and the longitudinal axes thereof are substantially parallel; a plate member attached to the other end of said upper link and depending therefrom to extend below the longitudinal axis of said lower link at such times as said links are in their initial position; elongated bidirectional power means the ends of which are respectively pivotally attached'to the enlarged end of said lower link and said plate member at locations below the longitudinal axis of said lower link at such times as said links are in their initial position.

(References on following page) UNITED STATES PATENTS Dement -2" June 9, 1936 Meacham July 2, 1940 5 Owens Apr. 17, 1945 Ross -1 May 31, 1949 Weaver Dec. 12, 1950 Broeker Mar. 27, 1951 Green June 22, 1954 Fritz June 21, 1955 Prowinsky Mar. 19, 1957 Johnson Sept. 17, 1957 FOREIGN PATENTS Italy Aug. 21, 1931 

